Found 1627 Articles for Computer Network

Wired Equivalent Privacy (WEP) is a security standard for wireless networks or WiFi. It was a part of the original IEEE 802.11 protocol. As wireless networks transmit data over radio waves, eavesdropping on wireless data transmissions is relatively easier than in wired networks connected by cables. WEP aims to provide the same level of security and confidentiality in wireless networks as in wired counterparts.Features of WEPWEP was introduced as a part of IEEE 802.11 standard in 1997.It was available for 802.11a and 802.11b devices.WEP uses encryption of data to make it unrecognizable to eavesdroppers.It uses RC4, a stream cipher, for ... Read More

Wi-Fi Protected Access (WPA) and Wi-Fi Protected Access 2 (WPA2) are security standards to protect network stations connected to WiFi networks. They were developed by WiFi Alliance for delivering sophisticated data encryption technologies and improved user authentication than the pre-existing Wired Equivalent Privacy (WEP).WiFi Protected Access (WPA)Wi-Fi Protected Access (WPA) was supported in IEEE 802.11i wireless networks and was proposed in 2004. It was backward-compatible with the existing WEP that led to its rapid, hassle-free adoption.The encryption method adopted in WPA is the Temporal Key Integrity Protocol (TKIP). TKIP includes per-packet key, integrity check, re-keying mechanism. It dynamically generates an ... Read More

IEEE 802.11 standard, popularly known as WiFi, lays down the architecture and specifications of wireless LANs (WLANs). WiFi or WLAN uses high frequency radio waves for connecting the nodes.There are several standards of IEEE 802.11 WLANs. The prominent among them are 802.11, 802.11a, 802.11b, 802.11g, 802.11n and 802.11p. All the standards use carrier-sense multiple access with collision avoidance (CSMA/CA). Also, they have support for both centralised base station based as well as ad hoc networks.IEEE 802.11IEEE 802.11 was the original version released in 1997. It provided 1 Mbps or 2 Mbps data rate in the 2.4 GHz band and used ... Read More

The IEEE 802.11 standard, lays down the architecture and specifications of wireless local area networks (WLANs). WLAN or WiFi uses high frequency radio waves instead of cables for connecting the devices in LAN. Users connected by WLANs can move around within the area of network coverage.The 802.11 MAC sublayer provides an abstraction of the physical layer to the logical link control sublayer and upper layers of the OSI network. It is responsible for encapsulating frames and describing frame formats.MAC Sublayer Frame Structure of IEEE 802.11The main fields of a frame in WLANs as laid down by IEEE 802.11 are as ... Read More

Static IP Address and Dynamic IP Address are both used to identify a computer on a network or on the Internet. Static IP address is provided by the Internet Service Provider and remains fixed till the system is connected to the network. Dynamic IP address is provided by the DHCP, generally a company gets a single static IP address and then generates the dynamic IP address for its computers within the organization's network. Read through this article to find out more about static and dynamic IP addresses and how they are different from each other. What is ... Read More

Both MAC Address and IP Address are used to identify a computer on a network or on the Internet. MAC address is provided by NIC Card's manufacturer and gives the physical address of a computer. IP address is provided by the Internet Service Provider and is called the logical address of a computer connected on a network.Read through this article to find out more about IP address and MAC address and how they are different from each other.What is an IP Address?Every unique instance linked to any computer communication network employing the TCP/IP communication protocols is given an IP address.When ... Read More

Inter – frame SpacesInter − frame spaces (IFS) are waiting periods between transmission of frames operating in the medium access control (MAC) sublayer where carrier-sense multiple access with collision avoidance (CSMA/CA) is used. These are techniques used to prevent collisions as defined in IEEE 802.11-based WLAN standard (Wi-Fi).IFS is the time period between completion of the transmission of the last frame and starting transmission of the next frame apart from the variable back-off period.The diagram below shows the different types of inter − frame spacing starting from the shortest duration (highest priority) to the longest duration (lowest priority). Among these, ... Read More

Transmit opportunity (TXOP) is a MAC layer feature used in IEEE 802.11-based wireless local area network (WLAN). TXOP defines the time duration for which a station can send frames after it has gained contention for the transmission medium. By providing this contention-free time period, TXOP aims to increase the throughput of high priority data, such as voice and video.TXOP is available in Quality of Service as part of Enhanced Distributed Channel Access (EDCA).Working PrincipleTXOP operates in the following sequence of steps −When a station in the WLAN has frames to send, it waits till it’s Network Allocation Vector (NAV) decrements ... Read More

Extended inter-frame spacing (EIFS), is a waiting period used in MAC layer of IEEE 802.11-based wireless local area network standard (WLAN standard). It is an additional waiting period used in addition to the mandatory DISF technique in case of corrupted frames.DISF (Distributed coordination function inter-frame spacing) is inserted before sending frames to avoid collisions in areas where carrier-sense multiple access with collision avoidance (CSMA/CA) is used. EISF is used for erroneous frames.Functioning of EIFSIn normal delivery of frames, DISF waiting period is good enough. However, when a previously received frame is corrupted, the DISF waiting period proves to be insufficient. ... Read More

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is a network protocol for carrier transmission that operates in the Medium Access Control (MAC) layer. CSMA/CA prevents collisions prior to their occurrence and is ideally used in wireless communications.Rate anomaly occurs when the performance of a high speed station is impaired due to a low speed station, thus reducing the average throughput of the entire wireless network.ExplanationThe CSMA/CA allows each station to send a single frame at a time. Before sending a frame, the station waits for a certain inter-frame spacing (IFS). Following the IFS, it sends the request to send ... Read More